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Solutions for Contractors

Aquatech has earned an excellent reputation among contractors for providing the expertise, the innovative thinking and prompt response necessary to address the full scope of project issues and environmental challenges. The following four case studies offer a brief illustration of how Aquatech manages a variety of potentially difficult situations.


Creek Bypass - Site Management in an Environmentally Sensitive Area

A contractor required Aquatech’s services to assist in a creek bypass and dewatering project which involved a pipeline replacement located in a difficult to reach area. Recognizing that the entire area was a flood plain that was subject to flooding during rainfalls, Aquatech recommended that the contractor install steel flume pipes to convey the dry weather flow of approximately 2m3/s. This design permitted the easy passage of aquatic species through the job site while minimizing the impacts the excavation would have upon the watercourse downstream. Working in conjunction with a number of stakeholders, including the owner, contractor, consultant and conservation authority, Aquatech proposed a dewatering system that would maintain a dry work area for the pipeline replacement. A complement of electric submersibles as well as diesel-driven generators and Dri-Prime pumps were utilized, the capacity of the pumping system being in excess of ½m3/s. Given the diesel driven pumping equipment had to be protected from potential flood damage, it was set back 170’ from the creek while the Dri-Prime pumps were able to self-prime on demand over the large amount of hose.

Dewatering – Turn-key Dewatering Solution amidst Complex Geology and Groundwater Conditions

Given the location on Toronto’s eastern waterfront, the Portlands area poses a combination of complex geography and challenging groundwater conditions. The soil structure is comprised of hydraulic fills, native organic silt and sands of varying gradation, which is underlain by shale bedrock. The groundwater level mirrors the level in nearby Lake Ontario and is a significant recharge boundary through a permeable (10-2 cm per second) aquifer system.

The contractor that was tasked with installing 330 metres of 96” cooling water pipe for the Portlands Energy Centre enlisted Aquatech’s assistance in providing a turnkey dewatering solution. Using a dual-sided wellpoint system to lower the water level one metre below the invert of the cooling pipe and five metres below the static water table, Aquatech successfully managed the dewatering on budget and helped the contractor complete the installation ahead of schedule.

Dewatering – Deep Servicing Trench Using Multi-level Vacuum Wellpoint Systems in a Sensitive Environmental Setting

One of Ontario’s premier homebuilders consistently relies upon Aquatech when developing the underground servicing in its residential communities. In this instance, working in the region of Whitchurch-Stouffville, one of the builder’s developments was bounded by the environmentally sensitive Rouge River system to the southwest. The geology was characterized as a dense glacial till capping an artesian and sub-artesian aquifer system that connected directly to the Rouge River and its tributaries. Aquatech’s responsibilities included the comprehensive management of groundwater control. They implemented both positive and passive pumping systems and managed the Permit To Take Water (PTTW) and discharge authorization to help support the construction of sanitary, storm and water servicing. In addition, Aquatech was responsible for overseeing the ongoing environmental monitoring program for the site to ensure there were no impacts to nearby water wells, creeks, tributaries and wet woodlots.

Sanitary Sewer Bypass – Major Bypass System Design with No Disruptions to Busy Downtown Core

With the prospect of rehabilitating an old trunk sewer in downtown Kingston, a contractor solicited Aquatech to design a bypass that not only dealt with the immediate sewer needs, but also caused minimal disruption to the environment, pedestrians as well as park and vehicle traffic. Aquatech responded by utilizing the existing combined sewer overflow tank to pump 3,200 USGPM of raw sewage over 3600’ with an increase in elevation of 50’, across several roads, through parks and adjacent to a national historic monument. The system operated for two months without any spillage or leaks from the pipeline. Meanwhile, additional pumping systems were installed at the end of the construction area, and the entire system ran alongside the St. Lawrence River, traversed parkland and five road crossings. Despite the extent of work involved, all roadways remained open for the duration of the project. The local utilities were so pleased with the results that they requested Aquatech’s services to manage a more complex section of sewer through the downtown core the following year.